Intermittent switch



Sept. 10, 1946. M F MlLLER 2,407,571

INTERMITTENT SWITCH Filed June' 16, 1944 Patented Sept. 10, 1946 UNITED STATES PATENT OFFICE 2,407,571 INTERMITTENT SWITCH Milo F. Miller, Kansas city, M0. Application June 16, 1944, Serial No. 540,586

(Cl. 20D-33) 6 Claims.

1 rIhis invention relates to electrical apparatus in the nature of intermittent switches employed in circuits where it is desired to periodically close a circuit to operate electrical apparatus, and the primary aim is to provide such a switch wherein the essential element constitutes a volume of conducting liquid, the surface whereof is raised and lowered in properly timed relation with respect to the appearance of a movable brush upon each of a series of contact plates.

Another important object of this invention is to provide an intermittent switch for electrical circuits having means for insuring that the closing and opening of the'circuit will occur only while a movable brush is passing across the faces of each of a number of short contact plates, said means including a specially formed, rotatable hollow element having current conducting liquid therein, the surface whereof is raised and lowered to and from engagement with a part of the rotatable element as the brush reaches and leaves each of the several contact plates.

Intermittent switches usually embody relatively expensive and complicated parts where arcing is effectively overcome. Switches of this type may be made to present a rugged structure which positively functions if the shiftable assembly thereof includes a properly contoured, hollow contact member timed as hereinafter set forth, so that no current will be present until the brush of the movable assembly is actually resting upon one of a series of contact plates. It is, therefore, the main object of this invention to provide a simple, inexpensive and efficient intermittent switch that embodies a volume of current conducting liquid, the level whereof may be raised and lowered in a predetermined manner.v

Minor objects o-f the invention will appear during the course of the. following specification, referring to the accompanying drawing wherein:

Fig. 1 is a top plan view of an intermittent switch made in accordance with the present invention.

Fig. 2`is a vertical longitudinal centra-l sectional view through the switch taken on line II-II of Fig. 1.

Fig. 3 is a transverse sectional view throughthe switch taken on line I-lII-of Fig. 2 and looking in the'direction of the arrows; and

Fig. 4 is a fragmentary sectional View of the hollow, rotatable element per se, entirely removed from association with the remaining parts of the switch.

This application is a continuation in part of my co-pending application, Serial No. 517,626,

filed January l0, 1944, in that the periodic switch disclosed therein, may be made as hereinafter set forth.

The switch about to be described may be used in the electrical system set down in my said co-pending application, and therefore, it will be understood that the circuit diagrammatically illustrated in Fig. 2, may be of any character so long as the switch assembly is disposed therein to periodically supply a number of electrical appliances Iii, I2, I4 and I6 with operating current.

The source of electrical supply, in the instance illustrated, is a conventional battery I8 and a conductor 2% .extends from this battery to the elongated, stationary contact memberv 24, supported in a casing of insulating material 26. Opposed to this elongated contact member 24, are a. number of relatively short Contact plates Z3, S, 32 and 34, each connected to their respective appliances Iii, I2, I4 and IG by conductors forming a part of the circuit. Other conductors join` appliances I, I2, I4 and IS with battery i8 and connection thereto may be as illustrated, or otherwise, to supply the proper voltage as the situation demands.

Referring now to the intermittent switch and the preferred manner of constructing the same, elongated contact member 24 is preferably in the form of a rack having teeth 35 formed thereon, which mesh with teeth 38 on a hollow, rotatable element 40, which is formed of conducting material as is Contact member 24.

Element 40 is hollow and the interior thereof is provided with a number of pockets 42, radially arranged and disposed to raise and lower the level of liquid 44 therein. This liquid may be any substance capable of flowing rapidly into pockets 42 as element 40 is rotated.

A part 46 in the form of a shaft extends axially through element 4U and into engagement with yoke 48, bifurcated as illustrated in Fig. 3, and continuing into a barrel 5i) having brush 52 slidably mounted therein. Spring 54 bears upon the inner end of brush 52 and yieldably maintains its outer end against the inner surface of one wall of case 2li or against contact plates 28, 3Q, 32 or 34, as the case may be. The sides of element 4f) areformed of non-conducting material and are in the nature of removable plates 5E, through which part 45 passes, as shown in Fig. 3.

An operating rod 58 is in connection with the parts just described, through the medium of a holder 6I) formed of non-conducting material and when the level of liquid 44 rises to a point where it is against part 46, current may flow from contact member 36 through element 40, liquid 44, part 46, yoke and barrel 43 and 50 respectively, and brush 52 to plate 28, if the parts of the switch are in the position shown in Fig. 2.

In constructing element 40, pockets 42 should be so numbered and arranged as to cause the level of liquid 44 to engage part 46 only immediately after brush 52 has reached the surface of one of the contact plates 28, 30, 32 or 34. Likewise, as the entire assembly, controlled by rod 58, is moved in the direction of the arrow, the level of liquid 44 should drop away from part 46 immediately before brush 52 leaves any one of these several contact points. In so doing, the brush and contact plates will be spared the detrimental efiect of arcing and clean surfaces may always be maintained in the switch.

The form of element 40 and member 24 is such that no slipping can occur between the areas thereof that are in contact, and therefore, when the switch is timed with regard to the level of liquid 44 and the disposition of pockets 42, the circuit will always be closed at the proper instant while brush 52 is upon one of the contact plates. The specific form of pockets 42 may be altered as desired and to suit conditions. Mercury has been found satisfactory as a liquid current conducting medium, and also as a liquid which will quickly leave part 46 as element 40 is rotated.

As illustrated in Figs. 2 and 4, the level of the liquid 44 when three pockets 42 are receiving the volume thereof, is high enough to contact part 46, but when parts of more than three pockets are below the level of liquid 44, that level will drop, as illustrated in Fig. 4, to leave part 46 and therefore, open the circuit. This liquid 44 may be introduced into element 40 by merely removing one of plates 56 for the same are removably attached in place by screws or analogous means 6U.

The manner of employing the intermittent switch and one preferred way of constructing the same has been made clear during the course of the specification, and since alterations may be made without departing from the spirit of the invention, it is desired to be limited only by the scope of the appended claims.

Having thus described the invention,` what is claimed as new and desired to be secured by Letters Patent is:

1. A switch of the kind described comprising an elongated stationary contact member; a se ries of relatively short, spaced apart contact plates; a brush disposed to move across the faces of the several plates of the series one at a time; a rotatable hollow element in constant contact with the elongated contact member and in electrical connection with the said brush; and a filling of current conducting liquid in the hollow element, said hollow element having its interior formed to raise and lower the level of the conducting liquid as the element is rotated over the relatively long contact member, the switch being closed when the liquid level is raised to a predetermined point and being opened when the liquid falls below said predetermined point, said hollow element being formed and disposed with respect to the brush to close and open the switch while the brush is on each of the relatively short contact plates.

2. In an intermittent switch of the kind described, an elongated stationary contact member; a series of relatively short contact plates; a brush movable across the faces of the said contact plates; a hollow rotatable element of conducting material in constant contact with the elongated contact member having an axially disposed part of conducting material in connection with the said brush and insulated from the rotatable element; and current conducting liquid Iin the hollow element and in contact therewith, said element being formed to cause the level of the liquid to shift to and from a point against the said part while the brush is on each of the relatively short contact plates.

3. In an intermittent switch of the kind described, an elongated stationary contact member; a series of relatively short contact plates; a brush movable across the faces of the said contact plates; a hollow rotatable element of conducting material in constant contact with the elongated contact member having an axially disposed part of conducting material in connection with the said brush and insulated from the rotatable element; and current conducting liquid in the hollow element and in contact therewith, said element being formed to cause the level of the liquid to shift to and from a .point against the said part while the brush is on each of the relatively short contact plates, said elongated contact member and the hollow rotatable member having interengaging surfaces to preclude slipping between the intercontacting areas thereof.

4. In an intermittent switch scribed, an elongated stationary contact member; a series of relatively Short contact plates; a brush movable across the faces of the said contact plates; a hollow rotatable element of conducting material in constant contact with the elongated contact member having an axially disposed part of conducting material in connection with the said brush and insulated from the rotatable element; and current conducting liquid in the hollow element and in contact therewith, said ele* ment being formed to cause the level of the liquid to shift to and from a point against the said part while the brush is on each of the relatively short contact plates, said elongated contact member being a rack, said rotatable member being a gear in mesh with the rack.

5. A switch of the character set forth in claim 2, wherein the hollow rotatable member is provided with a series of internal radial pockets to receive the liquid as the member is turned about its axis.

6. A Switch of the character set forth in claim 2, wherein the hollow rotatable member is provided with a series of radial pockets to receive the current conducting liquid, said Ipockets being arranged to raise the level of the liquid against the axially disposed part only when the brush is on one of the relatively short contact plates and to lower the level of the liquid to a point spaced from the said part when the brush is between the contact plates.

MILO F. MILLER.

of the kind de- 

